Fuel induction system



Feb. 17, 1959 E. OLSON FUEL .mnucnon SYSTEM 5 Sheets-Sheet 1 Filed Sept. 10, 1956 INVENTOR. 625726: (9230/:

ATTORNEY E. OLSON FUEL INDUCTION SYSTEM 3 Sheets-Sheet 2 W 1% n4! All.

INVENTOR. 525726: 523022 A 7' TOE/V15 Y Feb. 17, 1959 Feb. 17, 1959 Filed Sept. 10; 1956 E. OLSON 2,873,732

FUEL INDUCTION SYSTEM 5 Sheets-Sheet 5' v INVENTOR.

United States Patent FUEL INDUCTION SYSTEM Elmer Olson, Rochester, N. Y., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application September 10, 1956, Serial No. 608,797

Claims. 01. 123-119 The present invention relates to a fuel induction system of the type in which fuel is supplied in proportion to the mass of air flowing therethrough. The present invention is an improvement in the fuel induction system of the type shown in copending application Serial No. 608,853 Dolza, filed September 10, 1956.

In the present type fuel induction system, the mass of air flowing through the system is indicated by vacuum forces induced'by the flow of air through various parts of the induction passage. The .vacuum thus produced is conveyed to a vacuum actuated fuel control device wherein the quantity of fuel supplied increases with an increase in vacuum, indicative of increased air flow.

In'fuel induction systems of the same mass air flow type not utilizing the present invention, during idling a vacuum signal is transmitted to the vacuum responsive fuel control member fixing the quantity of fuel being supplied to the engine for proper idling. Thereafter, in opening the throttle from its idling position there is a temporary drop in control vacum prior to the induction passage air flow increasing sufliciently to raise the vacuum signal to that obtained at the time of idling. As the result of this vacuum drop an incorrect signal is temporarily fed to the vacum responsive fuel controlling mechanism reducing the quantity of fuel supplied and thereby leaning the combustible mixture to an extent causing a drop or lag in'engine power at a time when increased .power is being demanded. 1

The present improved fuel induction system includes means whereby the objective of a smoother flow of power is realized in effecting the transition from idling to normal running operation. The objective of smoother power flow is achieved in the present device by providing a system in which it is possible to delay the drop in idling vacuum until such time as the normal air flow through the induction system is adequate to relay an accurate indication of engine fuel requirements to the fuel controlling mechanism. 7 t 7 Further objects and advantages of the present invention will be apparent from a perusal of the detailed description which follows.

In the drawings:

."Figure 1 is a partially broken away elevational view of an engine utilizing the subject fuel induction system;

Figure 2 is a partially sectioned view of the venturi and vacuum control-signal passages;

Figure 3 is a graph illustrating the function of the present invention;

Figure 4 is a partially sectioned view of the fuel control metering system; and

- and described in copending application Serial No. 608,853

Dolza, filed September 10, 1956. Accordingly the system will be described in detail only in relation to the mechanism which specifically constitutes the subject Patented Feb. 17, 1959 matter of the present invention, or such other mechanism as is necessary to an understanding of said invention.

Referring to Figure l, the subject type fuel induction system indicated generally at 10 is shown mounted on a V-type engine 12. The fuel induction mechanism is disposed above and substantially intermediate the cyl-' inder banks 14 and 16. It is, of course, to be understood that the invention is in no way limited by the cylinder configuration and is equally adapted to in-line or other type engines.

In general the fuel induction system is housed in a shroud consisting of an upper casing 18 and a lower casing 20. Disposed within the shroud is an air inlet opening 22 which preferably has an air cleaner, not shown, associated therewith. Air in the shroud casing 22 is drawn into an air horn casing indicated generally at 24. Air from the air horn 24 passes into a plenum chamber 26 from whence the air is delivered through manifold passages 28 to the respective engine cylinders as described in copending application Serial No. 608,853 Dolza, filed September 10, 1956.

Fuel nozzles 30 are mounted in the lower ends of manifolds 28 adjacent the intake valves 32 of the respective cylinders and supply fuel thereto when the intake valves are open. Fuel is supplied through aconduit 34 to each fuel nozzle 30 from a fuel manifold 36'which is in turn supplied by a conduit 38 from a fuel supplying and metering device indicated generally at 40. The fuel nozzles are more fully described in copending application Serial No. 608,895, filed September 10, 1956, Dolza et al.

The fuel supplying and metering device 40, as shown in Figure 4, is mounted in a housing which includes a case 42 and a cover 44. A conduit 46 is formed in cover 44 and is supplied with fuel from a low pressure make-up pump, not shown. A float controlled valve mechanism 50 is also disposed in cover 44' and communicates with conduit 46 through a passage 52 to which filtered fuel is supplied in accordance with the vertical position of the valve member 54 as determined by the position of a pivoted float actuated arm 56. In the normal manner, as float 58 is raised and lowered a valve 54 will shut off or admit fuel into a fuel reservoir 60 provided in casing 42.

A constant displacement type pump which is driven at engine speed is mounted in the fuel reservoir and is adapted to pump fuel from the reservoir 60 to a conduit- 72 leading generally to a metering chamber 74.

Chamber 74 is separated from the fuel reservoir by a partition 76. A bore 78 is formed in the casing of chamseated upon the upper end of the plug 88. Valve 90 'blocks the flow of fuel. through conduit 86 with a force determined by the rate of a spring 92 which presses upon the ball check valve 90. The valve also includes a cylindrical sleeve 94 having a plurality of circumferentially disposedports 96 therein which communicate the fuel flowing around ball check valve to an annularly relieved portion 98 of sleeve 94. The annularly relieved portion 98 of sleeve 94 thereafter communicates with a passage 100 in the casing wall into which is threaded an adapter plug 102 connecting with the fuel manifold supplying conduit 38.

Sleeve 94 also has a set of peripherally disposed bypass or spill ports 104 above the ports 96. Ports 104 communicate the interior of sleeve 94 to the chamber 74 and thence through a passage 106 back to the fuel reservoir. To control the quantity of fuel bypassed through valve 80 back to reservoir 60 and hence the quantity of fuel supplied to the fuel nozzles, a cylinder 108 closed at the upper end is slidably mountedin sleeve 94. The open end of cylinder 108 terminates proximate spill ports 104 in sleeve 94. Fuel pressure within the valve body and which, as noted, is proportional to engine speed tends to move the cylinder 1'08 upwardly to open ports 104 and thereby bypass fuel to the resermm A linkage mechanism indicated generally at 110 and controlled by a diaphragm 112 exerts a force on top of the valve, as generally described in the aforementioned copending application Serial No. 608,853, filed September 10, 1956, which is proportionalto the quantity of air flowing through the system. Thus it will be seen that the quantity of fuel supplied to the nozzles 30 by metering valve 80 is proportional to the differential effect of engine speed, as manifested by fuel pressure, and the quantity of air flowing through the system,- as manifested by vacuum acting on diaphragm 112.

Other features of the subject type system such as the coasting shutoff mechanism 120 as well as the fuel enrichment devices 130 and 140 are described in detail in copending application Serial No. 608,853, filed September 10, 1956. Since these devices are not directly pertinent to the subject invention no further reference will be made thereto.

In Figure 2 an idle air bleed device 150 is provided in air horn casing 24 for bypassing air around athrottle 152 during the idle operation of the system. Device 150 includes a passage 154 terminating posterio'rly of the throttle valve 152, a second passage 156 terminating anteriorly of the throttle and a passage 158 connecting posterior-anterior passages 154 and 156. An adjustable valve 160 is mounted in the air horn casing 24 and provides a means whereby the quantity of bypass air may be varied.

Disposed in parallel with the idle air bleed device 150 is passage means for sensing the quantity or mass of air flowing through idle air bleed. The quantity sensing means includes a passage 162 communicating with the induction passage bore immediately anterior of throttle 152. Passage 162 connects with a somewhat larger chamber 164 in turn connected through a passage 166 to air bleed passage 154. Thus as idle air passes through passage 154 a vacuum is created in chamber 164 proportional to the quantity of said idle air. An ad justable needle valve 168 is mounted in the air horn casing and projects into passsage 166 in order to vary the magnitude of the low air flow vacuum signal which is created during. idling.

In order to convey the low air flow vacuum signal from the air born 24, an axial passage 170 is formed in the casing 24 and terminates in a perpendicularly disposed threaded boss 172. For ease of manufacture, passage 170 may be drilled or cored through the casing 24 and thereafter blocked off at the upper end by a plug 174.

Thus, with the throttle valve closed, as shown in Figure 2, air will be bypassed through passages 156, 158 and 154 creating a low air flow vacuum signal in chamber 164 and passage 170. This vacuum signal is conveyed to the diaphragm chamber 180 by a conduit 182 which connects with one nipple 184 of a T-plug 186 threadedly mounted in the vacuum chamber cover 188.

Upon the opening of throttle 152'the low air flow vacu-- um signal gradually reduces until itis essentially'nonexistent or at least has little further fuel control influence on the system. Therefore, additional means'is provided whereby a high air flow vacuum signal will be transmitted to diaphragm chamber 180 to maintain the control of meterin'g'valvefifi. To this end an annular chamber 190 is formed adjacent the throat of a venturi 192. The venturi itself is shown and described in copending application Serial No. 609,021, filed September 10, 1956, Barr. It is enough to say with regard to the venturi at this point that it is formed by the straight sided cylindrical air horn 24 into which projects a shaped plug 194 resulting in an annular venturi of a'type uniquely adapted to provide adequate air fiow through the system. The annular chamber 1% peripherally communicates at its radially inner endwith the venturi throat. Casing 24 is formed with an opening 196 in communication with the annular chamber and which opening is adapted to receive one end of conduit 198, the other end of which connects with the remaining nipple 200 of T-plug 186.

During conditions of low air flow, as at idling as described above, the air flow through venturi 192 is so low as to create virtually no vacuum in the annular chamber 190. However, as air flow increases during the transition from idling to normal operation the quantity of air flow through the venturi progressively increases and with it the magnitude of vacuum inannular chamber 190. Thus, the relationship between the vacuum signals in chambers 164, and is generally such that as one increases the other decreases with the increasing vacuum force tending to provide the fuel controlling signal in diaghragm chamber 180.

As already noted, however, before the advent of the present device, the transition from the idle vacuum signal to the normal, or high flow, vacuum signal has resulted in a temporary drop in vacuum in the diaphragm chamber 180. This situation is graphically illustrated in Figure 3 where horsepower is plotted against throttle opening to provide a power curve202. Assuming the engine'to be idling at point 204 it has been found, prior to the present invention, that in opening the throttle from idling po'si-" tion instead of the power following the solid curve there actually developed a loss or lag in power as shown by the dash curve portion 206. This power loss or lag reflects the temporary drop in-induction passage vacuum in making the transition from a low to a high air flow condition during the transitionary operation noted.

The present invention avoids this drop by providing separate passage means for conveying the high and low flow vacuum signals to the diaphragm, as already described, and further in providing means within the idle vacuum signal system whereby the vacuum control chamber is prevented from dropping too rapidly before the high flow vacuum signal reaches a value adequate to reflect the actual fuel requirements of the engine.

To this further end, an orifice 210 has been provided in nipple 184 of the T-plug 186. The orifice 210 is calibrated so as to insure that as throttle valve 152 opens and thereby reduces the vacuum force in chamber 164, the drop in vacuum or increase in pressure in conduit 182 is communicated very slowly to the diaphragm chamber 180. The fuel leaning effect of the vacuum drop thus being delayed until the high air flow vacuum signal in annular chamber 190 is adequate to maintain the vacuum signal in diaphragm chamber 180 at least substantially constant during the transition from idling to normal running operation.

It is to be understood that the delay in vacuum drop occasioned by the use of orifice 210 takes place over a very short space of time but the delay need only be long enough until air begins flowing through the venturi in a quantity suflicient to at least match the idle air'fiow signal.

While it has been convenient to connect both conduits 182 and 1132 to a common T-plug 186 it is equally possible that both of the conduits be individually connected to the casing 188 if this is desired. Similarly for ease of manufactureit is proposed to locate the orifice 210 inthe T-plug as shown. Here again the construction-may bemodified to provide the orifice elsewhere in the'low air flow vacuum signal system. It is, of course, obvious thatthe orifice 210. is removably disposed in the system such that various size orifices may be provided to more closely match the operating characteristics of particular engines. It is apparent that additional structural modifications may be made within the scope of teaching of the present device.

I claim: 1. A fuel control system comprising an induction passage; a venturi in said passage; valve means for controlling the flow of air through said passage; passage means for bypassing air around said valve when the valve is closed for idling operation; a nozzle posterior of said valve for supplying fuel to said induction passage; a controldevice for supplying fuel to said nozzle, said device including a fuel metering valve and diaphragm means connected to said valve and adapted to control the fuel flow therethrough in proportion to the mass of air flowing through said induction passage; first conduit means connecting said bypass passage with said diaphragm means; second conduit means communicating with said venturi and similarly connecting with said diaphragm means; and means provided in said first conduit for restricting the rate of vacuum change between said diaphragm means and the bypass passage.

2. A fuel control system comprising an induction passage; a venturi in said passage; valve means for controlling the flow of air through said passage; means for bypassing air around said valve when the valve is closed for idling operation, said bypass means including a first passage communicating with the induction passage posteriorly of the throttle, a second passage communicating with the induction passage anteriorly of the throttle and connecting with the first passage, and a third passage connected to said second passage; a nozzle posterior of said valve for supplying fuel to said induction passage; a control device for supplying fuel to said nozzle, said device including a fuel metering valve, a pump supplying fuel to said valve in proportion to engine speed, and diaphragm means connected to said valve and adapted to control the fuel flow therethrough in proportion to the mass of air flowing through said induction passage; first conduit means connecting said third passage with said diaphragm means; second conduit means communicating with said venturi and similarly connecting with said diaphragm means; and means provided in said first conduit for restricting the rate of vacuum change between said diaphragm means and the third passage.

3. A fuel control system comprising an induction pasto the flow of air therethrough; a nozzle posterior of said valve for supplying fuel to said induction passage; a control device forsupplying fuel to said nozzle, said device including a fuel metering valve and diaphragm means connected to said valve and adapted to control the fuel flow therethrough in direct proportion to the mass of air flowing through said induction passage; first conduit means for communicating the vacuum-force in the bypass passage means with said diaphragm means; sec-ond conduit means communicating said venturi vacuum with said diaphragm means; and means for delaying the vacuum drop in said first conduit during the initial opening movement of the throttle valve from its idling position.

5. A fuel control system as defined in claim 4 in which said vacuum drop delaying means comprises an orifice disposed in said first conduit.

6. A fuel induction system of the type in which fuel is supplied in direct proportion to the mass of air flowing a nozzle supplying fuel to said passage,'a valve controlling the flow of fuel to said nozzle, vacuum responsive means sage; a venturi in said passage; valve means for controlling the flow of air through said passage; a first passage means for bypassing air around said valve when the valve is closed for idling operation; a second passage means in parallel with and adapted to provide a vacuum force proportional to the quantity of air flow through said first passage means; a nozzle posterior of said valve for supplying fuel to said induction passage; a control device for supplying fuel to said nozzle, said device including a fuel metering valve and diaphragm means connected to said valve and adapted to control the fuel fiow therethrough in proportion to the mass of air flowing through said induction passage; first conduit means connecting said second passage means with said diaphragm means; second conduit means communicating with said venturi and similarly connecting with said diaphragm means; and means provided in said first conduit for restricting the rate of vacuum change between said diaphragm means and the second passage means.

4. A fuel control system comprising an induction passage; a venturi in said passage; means associated with and adapted to create a vacuum force proportional to the flow of air through said venturi; valve means for controlling the flow of air through said passage; passage means for bypassing air around said valve when the valve is closed for idling operation; said bypass passage means including means for creating a vacuum force proportional for controlling the position of said valve to supply fuel proportionately with the mass of air flowing through said induction passage, said means including a diaphragm exposed to atmospheric pressure on one side and vacuum on the other, first and second conduits connected intermediate the vacuum side of said diaphragm and the induction passage, said first passage being adapted to transmit a low air flow vacuum signal to said diaphragm to control said valve during the idling operation of said system, said second passage being adapted to transmit a high air flow vacuum signal to said diaphragm during the normal operation of said system, and means in said first passage to delay the vacuum drop therein during the transition from idling to normal operation.

7. A fuel induction system of the type in which fuel is supplied in direct proportion to the mass of air flowing through the system and comprising an induction passage, first and second means associated with said passage to respectively produce high and low air flow vacuum signals, a nozzle supplying fuel to said passage, a valve controlling the flow of fuel to said nozzle, vacuum responsive means for controlling the position of said valve to supply fuel proportionately with the mass of air flowing through said induction passage, said means including a diaphragm exposed to atmospheric pressure on one side and vacuum on the other, first and second conduits connected in parallel intermediate the vacuum side of said diaphragm and the induction passage, said first passage being adapted to transmit the low air flow vacuum signal to said diaphragm to control said valve during the idling operation of said system, said second passage being adapted to transmit the high air flow vacuum signal to said diaphragm during the normal operation of said system and means in said first passage to delay the vacuum drop therein during the transition from idling to normal operation.

8. A fuel induction system of the type in which fuel is supplied in direct proportion to the mass of air flowing through the system and comprising an induction passage, a nozzle supplying fuel to said passage, a valve controlling the flow of fuel to said nozzle, vacuum responsive means for controlling the position of said valve to supply fuel proportionately with the mass of air flowing through said induction passage, a linkage mechanism articulating said vacuum responsive means to said valve, first and second conduits connected intermediate the vacuum responsive means and the induction passage, said first passage being adapted to transmit a low air flow vacuum signal to said vacuum responsive means to control said valve during the idling operation of said system, said second passage being adapted to transmit a high air flow vacuum signal to said vacuum responsive means during the normal operation of said system, and means in said first passage to delay the vacuum drop therein during the transition from idling to normal operation.

9; A fuel induction system of the type in which fuel is supplied in direct proportion to the mass of air flowing through the system and comprising an induction passage, a nozzle supplying fuel to said passage, a valve controlling the flow of fuel to said nozzle, vacuum responsive means for controlling the position of said valve to supply fuel proportionately with the mass of air flowing through said induction passage, said means including a diaphragm having vacuum and atmospheric chambers associated therewith, first and second conduits connected intermediate the diaphragm vacuum chamber and the induction passage, said first passage being adapted to transmit a low air flow vacuum signal to said diaphragm to control said valve during the idling operation of said system, said second passage being adapted to transmit a high air flow vacuum signal to said diaphragm during the normal opeartion of said system, and means in said first passage to delay the vacuum drop therein during the transition from idling to normal operation.

10. A fuel induction system of the type in which fuel is supplied in direct proportion to the mass of air flowing through the system and comprising an induction passage,

means for controlling the position of said valve to supply fuel proportionately with the mass of air flowing through said induction passage, said means including a diaphragm having vacuum and atmospheric chambers associated therewith, a linkage mechanism articulating said dia phragm to said valve, first and second conduits connected intermediate the diaphragm vacuum chamber and the induction passage, said first passage'being adapted to transmit a low air flow vacuum signal to said diaphragm to control said valve during the idling operation ofsaid system, said second passage being adapted to transmit a high airflow vacuum signal to'said diaphragm during the normal operation ofsaid system, and an orifice in said first passage to delay the vacuum drop therein during the transition from idling to normal operation.

References Cited in the file of this patent UNITED STATES PATENTS 

